How stones can hold back the Sahara: Locals lead fight against deserts

FIFTEEN YEARS ago the Yatenga, a dry, dusty plateau in the heart of West Africa's Sahel, seemed fated to turn into desert. The thick forests that sustained it as the heart of an empire for 400 years in pre-colonial times had long been cut down, and population increase was rapidly exhausting the soil.

Many villages in this part of Burkino Faso had lost one- third to a half of their cultivable land within a decade. An expensive and highly mechanised EC-aided land conservation programme had failed to slow the deterioration.

But then, helped by Oxfam, the people of the area turned to an age-old remedy. They put lines of stones along the gentle contours of their fields.

The stone lines slowed the rate at which rainwater ran off the ground, and held back soil that used to be washed away. Within a few years crop yields doubled on the treated fields, and the technique had spread to more than 100 villages. In 1991-92, a year of good rains, the once-doomed Yatenga produced a surplus of more than 31,000 tons of grain.

Yesterday in Paris more than 100 nations formally signed a treaty that aims to spread the lesson of the Yatenga worldwide. The International Convention to Combat Desertification, which binds countries to draw up national plans to tackle the problem, is the first comprehensive assault on the massive loss of productive land that threatens one- quarter of the Earth's surface and the livelihoods of 900 million people.

It is the first international environmental treaty to have been conceived and completed through the initiative of developing countries, and the first to acknowledge that the ordinary people most affected by an environmental crisis know best how to tackle it.

'The convention commits countries to a bottom-up approach that involves the local populace,' said Harna Arba Diallo, a former minister in Burkino Faso, who is executive secretary of the treaty negotiations. 'Local communities will be consulted on what they believe is appropriate action, especially in the light of traditional knowledge and practices.'

History bears out the old saying, 'Forests precede civilisation. Deserts follow.'

Mesopotamia, one of civilisation's cradles, is now barren: the great city of Uruk, 50,000- strong in 3000 BC, is now just a bump in the sand. Plato compared the bare hills of Attica to 'the skeleton of a body wasted by disease'.

Much of North Africa turned to dust to fill Rome's granaries while the Haitian Hills, which Christopher Columbus described 'as green and lovely, filled with trees of a thousand kinds', are now bare and eroded.

Worldwide in the past 50 years, the soil over an area the size of India and China combined has seriously deteriorated as a result of man's actions. Three-quarters of Africa's productive dryland and 70 per cent of Asia's has degraded. The United Nations Environment Programme estimates that in all, the loss of land costs the world dollars 42bn ( pounds 28bn) a year.

Rich countries are affected, too. More than half of Australia's grazing lands - and more than three-quarters of US range-lands - are degraded. Most of the migrants from Central to North America come from degraded drylands, while more people from Bakel, in south-east Sudan, now live in France than in the villages they left behind.

Desertification is notusually caused by deserts expanding outwards; more commonly it breaks out in patches, like a skin disease, as land is overused. Gradually the patches grow and join together.

Traditionally dryland peoples developed social structures and sophisticated ways of managing the land, but these were often disrupted by colonialism, and after independence the trend was continued by the new governments.

Attempts to tackle desertification, in which the local people were rarely consulted or involved, often made things worse. Drilling boreholes to provide water attracted people and cattle, putting the land around them under intolerable pressure, while the EC's earthworks, built to contain desertification in the Yatenga, could soon be seen meandering through destroyed land.

The new treaty - demanded by Third World countries at the 1992 Rio Earth Summit as a quid pro quo for agreeing to the treaty combating global warming - aims to avoid past mistakes by starting with the people themselves, recognising that desertification has social causes, and involving them in finding the solutions.

There are success stories to give them encouragement. In the Panchmahal Hills, where the Indian states of Gujarat, Rajasthan and Madhya Pradesh meet, soil conservation measures undertaken by the local people have increased crop yields sharply and cut migration from the area.

Kenya's Machakos Valley was virtually written off in the 1930s, but its inhabitants have greatly increased its fertility, despite a five-fold increase in population.

Soil loss has been cut by two-thirds, and average incomes tripled, in the Tangbeihe River Basin in China.

Ambassador Bo Kjellen, the chairman of the negotiations, hopes that the treaty will mark a turning point in the international assistance for development. 'People are asking if large funding programmes have lost their purpose,' he said.

'If our convention can come up with a bottom-up approach, which integrates the physical factors with the social and economic issues, perhaps donor fatigue can be turned to enthusiasm.'